1. Technical Field
The present invention relates to electronic and data processing devices and systems, and more particularly relates to portable electronic and data processing devices and systems with built-in expansion and retraction capability.
2. Description of Related Art
Technological advances in the computer and communication industry have resulted in improved integration capabilities. For example, integrated circuit densities are increasing which allow more functionality to be packaged into integrated circuit (IC) devices. This allows computers and other types of electronic devices to be built with fewer discreet components than previously required. Fewer components means that the resulting product can be packaged in a smaller package. Laptop computers weighing 5 pounds and less have computing capability similar to that of mainframe computers that existed twenty years ago. Personal digital assistants and cell phones, both of which have built in computational capability, can easily fit in a shirt pocket using today's technology.
This increase in electronic packaging density is not without problems, however. Heat dissipation is rapidly becoming a critical limiting factor in system design, potentially limiting the ability to achieve full size reduction due to physical mass requirements for dissipation of heat generated by the electronic device.
In addition, some devices cannot take full advantage of electronic packaging shrinkage due to the human factor effect, where a device must maintain a certain physical size to allow ease of human interaction. Cell phones with keyboards are an example where a device cannot be shrunk to its absolute smallest physical size, but rather must maintain a certain physical mass to allow a user to conveniently input keystrokes on the keyboard. While certain of these devices, such as personal digital assistants, have attempted to overcome this hurdle by eliminating the keyboard, they have introduced their own problems by requiring a user to learn a new input language that allows interaction via a touch sensitive display screen.
Another concern with shrinkage of physical packaging is the loss of system configuration capability. For example, many types of personal computers are built with a tower type of chassis. The tower chassis has many different physical compartments, allowing for a single style of tower to support many different types of computer configurations. Drive bays can be populated with a mixture of hard disk drives, floppy disk drives, compact disk drives, DVD drives, etc., allowing for a computer system to be customizable for a particular application. Numerous card slots on a motherboard contained with the tower chassis are user accessible, allowing a user to further configure/customize their system to include different types of adapter cards such as display adapters, SCSI adapters, USB adapters, network adapters, modems, etc. Some of the flexibility provided by these tower chassis is lost when a user instead uses a portable electronic device such as a laptop computer. Laptops (and portable electronic devices in general) have limited upgrade capabilities. For example, a laptop may allow an installed floppy disk drive to be removed and replaced with a CD drive. PCMCIA cards also allow for limited add-on capability, such as by connecting an external hard disk drive to the laptop using a USB adapter that is PCMCIA compatible. However, the number of available PCMCIA slots is typically limited to one or two in current laptop computers. Docking stations have been introduced to partially mitigate this loss of upgradeability and functionality, where a laptop is docked into the docking station when a user is in their office or home. This docking station may provide functionality that is available to the user, but only while their laptop is actually docked in the station. Other types of portable electronic devices, such as digital cameras, cell phones, etc. generally only have a memory expansion slot. Thus, as devices get smaller and smaller, their adaptability and configurability is similarly reduced. The present invention is directed to solving these problems.